Vacuum pump



FIG. 1 is a perspective view of a vacuum pump showing our new design;

FIG. 2 is another perspective view;

FIG. 3 is a bottom view;

FIG. 4 is a rear side view;

FIG. 5 is a right side view;

FIG. 6 is a front view; and,

FIG. 7 is a left side view.

The broken line showing of elements shown throughout the drawings is included for the purpose of illustrating environmental matter and forms no part of the claimed design. 

The ornamental design for a vacuum pump, as shown and described. 